Mariano Duncan was a professional baseball player who played for several teams during his career. He was born in the Dominican Republic in 1963 and began playing baseball at a young age. He was signed by the Los Angeles Dodgers as an amateur free agent in 1982 and made his major league debut in 1985.

Duncan played primarily as a second baseman and shortstop during his career. He was known for his speed on the basepaths and his ability to hit for average. He was also a solid defensive player, with a strong arm and good range.

Duncan spent the first six years of his career with the Dodgers, where he was a key part of the team's success in the late 1980s. He was a member of the Dodgers' World Series championship team in 1988, and he was named to the All-Star team in 1994.

After leaving the Dodgers, Duncan played for several other teams, including the Cincinnati Reds, Philadelphia Phillies, and New York Yankees. He continued to be a productive player, hitting over .300 in several seasons and helping his teams reach the playoffs.

Duncan retired from baseball in 1997, finishing his career with a .267 batting average, 72 home runs, and 536 runs batted in. He also stole 109 bases and scored 675 runs.

After his playing career ended, Duncan became a coach and manager in the minor leagues. He also worked as a coach for several major league teams, including the Philadelphia Phillies, Chicago Cubs, and Cincinnati Reds.

Overall, Mariano Duncan was a talented and versatile player who had a successful career in baseball. He was a key contributor to several championship teams and was known for his speed, hitting ability, and solid defense. After retiring from playing, he continued to be involved in the game as a coach and manager, helping to develop the next generation of baseball players.